Container

ABSTRACT

The invention relates to a container for storage and transport of liquids with the aim of maintaining the temperature of the liquid as constant as possible by insulation, the insulation ( 2, 2   a,    2   b ) of the container being disposed within the container and fastened ( 3 ) to the walls of the container. The insulation ( 2, 2   a,    2   b ) consists of thermally treated timber having a high insulation coefficient and good dimensional stability.

This invention relates to a container for storage or transport ofliquids, with the aim of maintaining the temperature of the liquid asconstant as possible by means of insulation, the container insulationbeing disposed within the container and fastened to the walls of thecontainer.

The insulation consists of wood blocks placed closely together andfastened to the inner wall of the container. The next layer of woodblocks are disposed closely adjacent each other and fastened to thepreceding layer, and/or at right angles to the preceding layer so as toachieve maximal density of the insulation. The number of wooden layersis determined by the thickness of the timber and of the insulation powerdesired for the container.

In previously known insulated containers, the insulating material isdisposed on the outer side of the container. There are a number of caseswhere cargo tanks of ships have been provided with insulation on theinner side, however, in those cases, the insulation has been made ofglass building blocks, or as an alternative, the insulation material hasbeen shielded by an inner tank made of thinner sheet metal in order toprotect the insulating material from direct contact with the liquid/oilstored in the container. Insulation provided on the outer side of a shipcargo tank is a costly solution, requiring freely placed tanks and/or anempty air space around the insulated tanks. Currently known bitumen oroil tanks provided with glass block insulation on the inner side or withinsulation material shielded by a thin inner tank require an extremelycostly manufacturing method, in addition to precious materials.

Previously known solutions comprising wood insulation materials disposedwithin the container have been disclosed by relatively old patentspecifications, such as e.g. GB 800,008, GB 921,696, U.S. Pat. No.2,859,895, U.S. Pat. No. 3,026,577 and U.S. Pat. No. 3,030,669. GBpatent specification 800,008 recommends balsa wood, which is alightweight kind of timber whose insulating coefficient is fairly good.

The present invention has the purpose of providing a containerinsulation that is light, durable, straighforward and inexpensive andwhose insulation power is equal, or even superior to that of containersprovided with thick insulation materials on the outer side. Thecontainer in accordance with the invention is characterised by aninsulation made of thermally treated timber with a high insulationcoefficient and good dimensional stability. The timber may consist ofquite ordinary Finnish softwood, such as spruce or pine. Variousembodiments of the invention are described in the dependent claims ofthe set of claims.

The invention yields the following benefits: thermally treated timber

-   -   has an insulation coefficient by approx. 25% higher than that of        commonly known usual timber. This results in a low temperature        maintained on the outer side of the container.    -   Does not vary under alterations of temperature and moisture    -   Does not absorb liquids    -   Has a service life much longer than that of untreated timber    -   Is not exposed to fire hazards since placed within the container    -   Is harmless to the environment and easily replaceable,        consequently will not form hazardous waste    -   Is chemically resistant and stands hot liquids and gases    -   Increases the strength of the inside of the container.

Disposing the insulation on the inner side of the container is a bettersolution for technical considerations of space as well. It enablesthicker insulation to be readily provided e.g. in the upper parts and inthe lid of the container, where heat tends to escape. In ships, ballasttanks in contact with containers insulated in accordance with theinvention are not exposed to heat or condensation damage, since a lowtemperature is maintained outside the container.

The invention is described below with the aid of a number of examplesand with reference to the accompanying drawings, in which:

FIG. 1 illustrates a container wall viewed in partial section fromwithin the container.

FIG. 2 illustrates an enlarged section II-II of FIG. 1.

FIG. 3 is a cross-sectional view of a ship provided with an insulatedcontainer surrounded by ballast tanks.

FIG. 4 illustrates an insulated pressure vessel.

FIG. 5 illustrates a rock container.

FIG. 6 illustrates an insulation comprising two layers of thermallytreated timber and

FIG. 7 illustrates an embodiment in which the second thermally treatedtimber layer has been replaced with cellular plastic, such aspolyurethane.

The purpose of the container may be storage or transport of liquids,with the aim to maintain the temperature of the liquid on a level asconstant as possibleby means of insulation. The insulation 2, 2 a, 2 bof the container is situated within the container and fastened 3 to thewalls 1 of the container. The insulation 2, 2 a, 2 b consists ofthermally treated timber, whose insulation coefficient is high anddimensional stability is good. The container may be a transportablecontainer or an oil cistern. It may also be a ballast tank 5 in a ship.The container may be a pressure vessel (FIG. 4) allowing storage of aliquid, such as water, under high pressure, e.g. 15-25 bars, and at atemperature e.g. in the range 170-200° C., and applicable as an energysource for a turbine or a steam engine. The container may consists of acavity in the soil, such as a container cavity excavated by blasting inthe rock (FIG. 5). Insulation of a second, lighter material, such ascellular plastic 4, e.g. polyurethane, polystyrene or the like, may beprovided between the timber insulation 2 and the container wall 1.

Calculations and empirical tests have proved that, say, the transport ofheavy oil at a temperature of 60° C. consumes 4 to 10 tons of oil perday for heating of the oil, depending on the tank volume. When acontainer in accordance with the invention is used, the consumption iscut to 0.4 to 0.5 tons of oil per day. A substantial economy is thusachieved.

Thus, the insulation coefficient of a cargo container or any othersimilar container insulated in accordance with the invention will behigh enough even for profitable transport of heat energy from thecooling water of a nuclear power plant to adequate sites for energyrecovery, such as district heating, for instance. At present, the heatenergy of cooling water is conducted off-shore.

An insulation disposed within the container makes it very easy tomeasure the surface temperature on the outside of the receptacle, tankor cargo container and thus to calculate the loss of heat, and ifnecessary , to provide supplementary insulation where desired.

1. A container for the transport and storage of liquids with the aim ofmaintaining the temperature of the liquid as constant as possible bymeans of insulation, the insulation (2, 2 a, 2 b) of the container beingdisposed within the container and fastened (3) to the walls of thecontainer, characterised in that the insulation (2, 2 a, 2 b) consistsof thermally treated timber having a high insulation coefficient andgood dimensional stability.
 2. A container as defined in claim 1,characterised in that the container is a transportable cargo containeror an oil tank.
 3. A container as defined in claim 1, characterised inthat the container is a ballast tank in a ship.
 4. A container asdefined in claim 1, characterised in that the container is a pressurevessel for storage of a liquid, such as water, under high pressure, e.g.15 to 25 bars and at the temperature e.g. in the range of 170 to 200°C., which can be utilised as the energy source of a turbine or a steamengine.
 5. A container as defined in claim 1, characterised in that thecontainer is a cavity in the soil, such as a container cavity excavatedby blasting in the rock.
 6. A container as defined in claim 1,characterised in that an insulation of a second, lighter material, suchas cellular plastic (4), e.g. polyurethane, polystyrene or the like, isprovided between the timber insulation and the container wall.
 7. Acontainer as defined in claim 1, characterised in that a thickerinsulation (2 b) layer is provided in the upper part of the container.